Voice Leading in Root Motion by Second (Seventh) and Third (Sixth) Root motion by seconds and thirds is less propulsive and more problematic than motion by fourth or fifth, because the chords are closer together, and thus parallel fifths and octaves are more likely. This is actually fortunate, because it means that there is generally only one common way to move by each kind of motion, which can be learned quickly, and should be used in almost all cases.
Motion by Third Chords that lie a third apart from each other will share two common tones, and only the third will differ, by second. The standard way of moving between these chords is to retain both of the two common tones, and move the remaining voice by step to complete the chord. Complete the following progressions:
Probably the most important example of this kind of motion is the movement between
IV and ii.
Note that there are few other options for this kind of motion. If you encounter a situation in which it will not work (which is rare), the you might try creating a voice exchange between the two voices that should otherwise hold their pitches. However, in general, any solution other than the standard solution will involve a lot of awkward skipping, leaping, and doubling.
First Inversion and the 5-6 Technique Generally, first-inversion triads should depart by step, and so their roots do not generally move by third. However, they can be approached by third. The most important version of this is for the roots to move down by third, while the second chord is in first inversion; since the bass is a third higher than the root, this has the effect of keeping the bass in one place. In this procedure, the fifth of the first chord will step upwards, becoming the new root – but also taking the position of a sixth above the common bass note (hence the figured bass symbol ); this is why this procedure is referred to as the 5-6 technique. Note that while it is possible to make the change with only one voice moving, you will usually want to change a second voice as well, to improve the doubling.
^
The most common use of the 5-6 technique is to allow chords to rise by step in more or less parallel motion without creating parallel fifths. This is another reason why we will often want to move another
voice and change the doubling between the two chords: to prevent parallel octaves. Ideally, we will usually alternate between doubling the root and the fifth. Complete the following sequential assent in evaded parallel motion using the 5-6 technique, and resolve the cadence:
^
It is important to remember that the figured bass symbol is not an inversion symbol; it is melodic elaboration of the preceding , which is why there is a line between the two symbols. It is important to be aware of the distinctions between the following three markings:
)
I ^ I) ppppppppp^ I
vi^
means shifting from the root position of the tonic chord to its first inversion. means keeping the same bass note and shifting the fifth up to a sixth, while remaining a tonic chord. is the same motion as the previous, but implies that the root has changed; this kind of analysis should not be employed without a compelling reason why the root should be seen to change (and doubly so in this case, since is a very rare chord).
vi^
Motion by Second in Root Position Chords whose roots lie a second apart contain no pitches in common, and (as suggested in the previous section) are at very high risk of parallel fifths and octaves. Hence, it is virtually a requirement that when these chords appear in root position, the upper voices must move in contrary motion to the second in the bass (note that this will occasionally appear as a seventh instead, in which case the motion will all be in the same direction; but motion by second is far more common). Each voice moves contrary to the bass to the nearest chord tone; two will move by step, and one will skip by third. Complete the following progressions by contrary motion:
This is almost the only possible solution, as neither the root nor the fifth may move in similar motion with the bass. However, the third sometime can, which will result in a doubled third. This should not be
done without a good reason, but it is the standard procedure in the deceptive cadence ( the third is the leading tone, which needs to resolve.
V - vi), in which
Complete the following deceptive cadences. The upper voices should look like an Authentic Cadence using contrary motion, except that the leading tone resolves.
Root Motion by Second in First Inversion and Fauxbourdon There is one circumstance under which true parallel motion by second is possible: in first inversion triads, using only three voices – and, in particular, this requires that the fifth be placed lower than the root (which usually means close position). The reason that this is okay is that there is no interval of a fifth – it is inverted into a fourth, and there is no prohibition against parallel fourths. However, we cannot add a fourth voice in parallel, because it would cause parallel octaves. As usual, the solution is that when using four voices, the fourth voice alternates between doubling the root and doubling the fifth. This is very much like the most characteristic progression in a Renaissance genre called fauxbourdon, and while this is strictly an inaccurate use of the word, many theorists use the term as a nickname for this procedure. Complete the following sequence-like progression in imitation of fauxbourdon, then complete the cadence:
